1. Field of the Invention
This invention relates to material handling excavator buckets and, more particularly, to attachment assemblies for use with excavator buckets that function much like a "thumb" to enable an excavator operator to grab or grip an object between an excavator bucket and the clamping assembly, and for use with excavator buckets that function much like a "claw" to enable an excavator operator to break or rip through a hard-surfaced material.
2. Brief Description of the Prior Art
Backhoes and other similar excavator machines that employ excavating buckets have been fitted with mechanical attachments, such as clamping assemblies to enable a machine operator to grab or pickup an object by gripping the object between the bucket and the clamping assembly, or with ripping assemblies to enable a machine operator to break rip through a hard-surfaced material. Backhoe buckets typically open rearward toward the operator and are designed to be loaded toward the operator.
Clamping assemblies heretofore have been mounted to the the dipstick boom--bucket connection between the operator and the bucket so that the bucket could be pivoted outward away from the clamping assembly for positioning over an object, and so that the bucket could then be pivoted rearward toward the clamping assembly for grabbing the object. Such a clamping assembly functions much like a "thumb" to enable the machine operator to pick up an object that could not be conveniently picked up by the bucket alone. For example, where a backhoe would be employed to dig a cavity for a utility vault, with the provision of a suitable bucket clamping assembly the backhoe operator could grab the utility vault and set it into the cavity without requiring the use of other machines or equipment. Likewise, the provision of a suitable bucket clamping assembly could permit the backhoe operator to conveniently grab a boulder or other object and lift it out of the way or place it in a desired location.
Ground-breaking attachments, such as cutting or breaking "claws", have been mounted to the end of an excavator "dipstick" boom, in place of the excavator bucket assembly, so that the excavator could be employed to break up, or rip through, ground or pavement that could not be broken up by the bucket assembly by itself. For example, the ground or pavement might be too hard for a bucket, having muliple teeth that share the downward force of the dipstick action and so dissipate the breaking or cutting force of the bucket teeth. Or, the ground or pavement may have to be broken or cut along a relatively narrow path, narrower than the width of the bucket teeth so that the bucket could not be usefully employed in that case.
Bucket clamping assemblies, i.e. bucket "thumbs", that have been heretofore proposed have suffered from any one of a number of deficiencies. Some such thumbs have either required permanent mounting to the excavator bucket or have required disassembly of the bucket mounting to remove the thumb from the bucket. Other such thumbs have fixed, unalterable arrangement of pickup teeth which renders the thumb awkward or impossible to use for picking up certain kinds or shapes of objects.
Excavator breakers or rippers that have been hertofore proposed have also suffered from any one of a number of deficiencies. Substitution of a breaking or ripping "claw" for the bucket assembly can be uneconomical in that the attachment assembly for both a bucket and a cutter or breaker "claw" requires a duplication of elements. Also, having to replace the bucket with a "claw" is a time-consuming procedure.
And, heretofore, there has been no mechanically-simple attachment for an excavator bucket that could be employed to provide either a gripping "thumb" or a ripping "claw", of both.